Dietary supplement of 25-hydroxyvitamin D3 in weaned piglets

It is generally believed that 25-hydroxyvitamin D3 (25(OH)D₃) has higher bio-potency than vitamin D3, which enhances calcium and phosphorous absorption, but also regulates immune functions and inhibits pathogenic microorganisms. Moreover, previous studies have demonstrated that 1,25-dihydroxyvitamin D3 could inhibit the expression of pro-inflammatory cytokines and T cells proliferation in vitro. However, little work has been done on dietary supplementation of 25(OH)D3 on piglets. Therefore, the aim of this study was to investigate the effects of dietary supplementation with different doses of 25(OH)D₃ on growth performance, immune function and anti-oxidative capacity of weaned piglets. For this purpose, a total of 35 weaned pigs (crossbred Duroc × (Landrace × Yorkshire)) were selected for a 21-d trial. The piglets (6.61 ± 0.39 kg) were divided into five treatment groups and fed diets supplemented with 5.5, 43.0, 80.5, 118.0 and 155.5 µg 25(OH)D₃/kg, respectively. The treatment with 5.5 µg 25(OH)D₃/kg was set as the control group. Average daily gain (ADG), average daily feed intake (ADFI) and feed to gain ratio (F/G) were measured by weighing animals and feed, respectively. At the end of the trial, on d22, blood samples were taken from all pigs after a fasting period of 12h.

For ADG, ADFI and F/G no significant differences were observed between treatments. However, dietary supplementation of 25(OH)D₃ increased significantly serum concentration of 25(OH)D₃. Increasing dietary 25(OH)D₃ levels did decrease the frequency of CD3+CD4+ and CD3+CD8+ T cells, and the serum level of complement component 3. Supplementation of 80.5 and 118.0 µg 25(OH)D3/kg showed an enhanced activity of serum glutathione peroxidase and the addition of 43.0 µg 25(OH)D₃/kg increased the malondialdehyde concentration. All in all, feeding a high-dose of 25(OH)D₃ to weaned pigs seemed to partly improve immune functions and the antioxidant capacity.

Yang, J., Tian, G., Chen, D., Zheng, P., Yu, J., Mao, X., He, J., Luo, Y., Luo, Y., Luo, J., Huang, Z., Yu, B. (2019). Effects of dietary 25-hydroxyvitamin D3 supplementation on growth performance, immune function and antioxidative capacity in weaned piglets. Archives of Animal Nutrition, 73(1), 44-51. https://doi.org/10.1080/1745039X.2018.1560113